Textile substrates for image printing

ABSTRACT

A textile coated with a coating having cationic and repellant properties, thereby accepting an image thereon more readily.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of copending U.S. patent applicationSer. No. 09/772,800, filed on Jan. 30, 2001.

BACKGROUND

The present invention generally relates to placing images on textiles,and in particular, to the treatment of textiles for enhancing thedefinition of the image placed upon the textile.

Images are placed upon a substrate by various methods such as digitalprinting. Digital printing is the process of placing various smallpredetermined quantities of a colorant, known as pixels, inpredetermined matrix zones of a substrate. Colorants can include dyes,pigments, polymeric colorants, or combinations thereof. Additionally,colorants can include different types and colors of dyes and/orpigments. The pixels can be placed on the substrate by various methods,such as ink jet printing. Typically, digital printing uses a limitedsmall number of different colorants, and only one of these colorants isused for a particular pixel. Variations in colors and shades in digitalprinting is generally accomplished in digital printing by positioningdifferent colored pixels in adjacent or near-by matrix zones. Althoughthe actual color of the individual pixels is not changed, the impressionto a viewer is that the area containing the different colored pixels isa color or shade that is different than any of the actual pixels in theassociated area. The impression is created because the pixels are ofsuch a small nature that the viewer cannot readily perceive theindividual pixels, and perceives more of an average of the pixels.

Placing images on textiles presents various difficulties not experiencedin all substrates. It has been discovered by the inventors of thepresent invention that, due to the nature of the material in a textile,or the construction of the textile, the color medium (such as ink) usedto place the image on the textile may not fill the intended zone for themedium, may bleed outside of the intended zone, or may be absorbed intothe textile substrate. If the color medium does not fill the intendedzone, the image placed on the textile can lose color intensity due tothe presence of the underlying textile substrate color. If the colormedium is absorbed into the textile, color intensity can be lost due toat least a portion of the color medium being disposed in an area of thetextile that cannot be seen, and/or by the color medium failing to fillthe intended zone. If the color medium bleeds outside of the intendedzone, image acuity and intensity can be impacted.

These problems are of greater concern with digital printing, where theintended zones for the color medium are smaller and closer together.Furthermore, methods to correct these problems can increase the abilityof the textile substrate to lose colorant due to rubbing contact withanother surface. Therefore, there is a need for textiles, textiletreatments, and methods which reduce the difficulties in placing animage on textiles.

DETAILED DESCRIPTION

In one embodiment of the present invention, a coating having cationicand repellant characteristics are coated onto the surface of a textileto receive an image by processes such as digital printing. The coatingcan be a combination of a cationic material and a repellant finish.

Generally, the textile materials can include banner or sign fabrics,upholstery fabrics, drapery fabrics, napery fabrics, carpeting, and thelike. The textile can be a woven, knitted, non-woven material, tuftedmaterials, and the like. Woven textiles can include, but are not limitedto, satin, poplin, and crepe weave textiles. In one embodiment, thetextile is a woven textile, and has from about 15 to about 75 picks perinch, from about 15 to about 175 ends per inch, and can be a satinweave. Knit textiles can include, but are not limited to, circular knit,warp knit, and warp knit with a microdenier face. In one embodiment, thetextile is a warp knit fabric with from about 12 to about 50 wales perinch, and from about 10 to about 60 courses per inch. Such textilematerials can be formed of natural or synthetic fibers, such aspolyester, nylon, wool and acrylic, including textile materialscontaining mixtures of such natural and synthetic fibers.

Cationic material are materials that have a positive charge. It isbelieved that the cationic material helps hold the color medium on thesurface of the intended zone, thereby reducing any bleeding of the colormedium into unintended areas or absorption of the color medium into thetextile. Cationic materials that can be used for the present inventioninclude, but are not limited to, polymeric, non-polymeric organiccompounds, and metal salts. Polymeric cationic materials andnon-polymeric organic cationic materials include nitrogen containingmaterials and phosphorus containing materials. Nitrogen containingcationic materials include, but are not limited to, primary amine (suchas polyvinylamine or polyallyamine), secondary amine, tertiary amine,quaternary amine, and amines converted to cationic amines under acidicconditions. Examples of nitrogen containing cationic polymer materialsinclude homopolymers or copolymers of cationic monomers. Cationicmonomers can include diallyldimethylammonium chloride, ormethacrylamidopropyltrimethyl ammonium chloride, or the like. Phosphoruscontaining cationic material include, but are not limited to, thephosphonium group. Examples of a phosphonium group cationic materialinclude stearyltributyl phosphonium bromide, or the like.

Metal salts that can be used for the present invention include watersoluble salts of cations from Group II, Group III, or the TransitionMetals of the Periodic Table. Examples include magnesium, calcium,aluminum, zinc, and zirconium. In a preferred embodiment, the salts havean anion of a weak acid, such as acetate forming or the like.

It has been found that the use of a combination of quaternary polymerand a multivalent metal salt as the cationic coating material isparticularly effective as a treatment for fabric to receive an imagesuch as from digital printing.

Repellant finishes include fluorochemicals, silicones, resin-basedfinishes, waxes, wax-metal emulsions, organometallic complexes, andcombinations thereof. It is believed that the repellant properties ofthe repellant finishes help prevent the color medium from being absorbedinto the textile, and facilitates allowing the color medium to fill theentire intended zone for the color medium.

Fluorochemical repellants include chemicals that contain perfluorocarbongroups. In one embodiment, the fluorochemical repellants are theproducts of copolymers of perfluoroalkyl acrylates or methacrylates withother comonomers. The comonomers include esters of acrylic ormethacrylic acid containing alkyl groups, alkylamide groups, orpolyether groups. In one embodiment, the Fluorochemical repellants canbe emulsions or solvent solutions for application to the textilematerial.

Silicone repellants include polymers of methyl(hydrogen)siloxane anddimethylsiloxane. In one embodiment, the silicones are an aqueousemulsion or a solvent solution for application to the textile material.

Resin-based finishes include modified melamine formaldehyde resin basedfinishes, and can be blended with waxes. In one embodiment, theresin-based finishes are a water soluble material such as Aerotex M3from BF Goodrich for application to the textile material.

The image on the textile is created by a colorant. The colorant can bedyes, pigments, polymeric colorants, or a combination thereof, and canbe a component of a material such as an ink. The ink can be an aqueousand/or non-aqueous solution based material, with the colorant being adispersion or a solution therein. An example of the aqueous dispersiontype ink is the DI Series (Yellow GWL, etc.) from Ciba, Inc. An exampleof a non-aqueous solvent type ink is the PzO Series (cyan, magenta,yellow etc.) from A.R. Monteith. Inc.

In a procedure of the present invention, the coating having cationic andrepellant properties is applied to the textile and then the image isplaced upon the surface of the textile having the coating thereon. Inone embodiment, the coating is applied to the textile substrate in anaqueous solution. The aqueous solution can be applied to the surface ofthe textile to receive the image, or the entire textile can be dippedinto the aqueous solution. After the aqueous coating is place on thetextile, the textile is typically squeezed between rolls to removeexcess aqueous solution, and then dried. The image can be placed on thetextile using digital printing, such as from a digital or ink jetprinter.

The present invention can be further understood with reference to thefollowing examples:

EXAMPLES 1-6

A polyester fabric was dipped into a variety of aqueous baths of thechemical coatings listed below in Table 1. The fabric was a Sateen Weavewith 152 ends per inch and 70 picks per inch. The warp yarn was a1/70/34 polyester, warp drawn yarn. The fill yarn was a 1/150/34textured polyester yarn. The base fabric weighed about 3.1 oz/sq. yd.TABLE 1 AR AR AR AR % ΔE ΔE ΔE ΔE Black Black Red Red Example ChemicalFormulation add-on Black Red Yellow Blue Warp Fill Warp Fill Control N/A  0% 65.6 53.8 47.5 51.5 1.3 2.3 1.3 3.3 1 15% Polycat M-30 3.2% 69.463.5 65.9 58.2 1 1.2 1 1.2 3% Foraperle 501 2 15% Polycat M-30 3.5% 69.563.8 65.6 57.3 1 1.2 1 1.2 1% Foraperle 501 3 15% Polycat M-30 3.0% 69.563.0 64.6 56.3 1 1.2 1 1.3 0.5% Foraperle 501 4 15% Polycat M-30 3.0%67.8 60.6 56.7 57.8 1 1 1 1 0.5% Repearl 8025 5 35% Nalco 2010 4.3% 70.669.1 77.4 59.5 1 1.3 1 1.2 1% Foraperle 501 6 25% Dow Coming 4.5% 68.438.0 45.3 37.4 1 1.3 1 1.3 5700

In Table 1, the percentages of the chemicals listed in the ChemicalFormulation column are by weight of the total aqueous bath of thechemical coatings. In the Chemical Formulation column of Table 1,Polycat M-30 is a quanternary stilbene vinyl copolymer by Peach StateLabs; Foraperle 501 is a fluorochemical dispersion by Atofina; Repearl8025 is a fluorochemical dispersion by Mitsubishi Chemical; and Nalco2010 is a diallyidimethylammonium chloride (DADMAC) polymer by Nalco.Dow Corning 5700 listed as the Chemical Formulation in Example 6, is a3-(trimethoxysilyl)propydimethyloctadecyl ammonium chloride by DowCorning, and demonstrates the present invention utilizing a coatingchemical having both cationic and hydrophobic properties. Anothercoating chemical that can be used for the present invention that haveboth cationic and hydrophobic properties includes melamine-formaldehyderesin.

The chemical coatings were applied in aqueous form by dipping the fabricinto a water based bath of the chemicals listed in Table 1. After thefabric was coated with the aqueous solution of the chemical coatings,the coated fabric was squeezed between rolls and dried at 360 F for 2minutes. The % of add-on is the difference between the weight of thefabric before and after the chemical coatings are applied, divided bythe weight of the fabric before addition of the chemical coatings andmultiplied by 100.

The coated fabric was printed with an HP 660C digital printer with atest pattern of 1 inch diameter black, red, yellow, and red dots, and 4pt. black and red lines. The inks used were pigment based (Black), oracid dye based (red, yellow, blue).

The color of the dots was measured with a HunterLab DP-9000 colorometer.The variations in color intensity between samples and the fabricbackground was measured with a modification of The Engineering Societyfor Advancing Mobility Land Sea Air and Space Textile Test method SAEJ-1885, “(R) Accelerated Exposure of Automotive Interior Trim ComponentsUsing a Controlled Irradiance Water Cooled Xenon-Arc Apparatus”. Themodification of the test was that the initial measurement was on thebackground (or area not printed) and the final measurement was on theprinted area. The color intensity, ΔE_(p), is generally calculated bythe following equation:ΔE _(p)=((L _(background) −L _(printed))²+(a _(background) −a_(printed))²+(b _(background) −b* _(printed))²)^(1/2)wherein ΔE_(p) represents the difference in color between the backgroundfabric and the fabric after printing. L, a, and b are the colorcoordinates; wherein L is a measure of the lightness and darkness of thecolored fabric; a is a measure of the redness or greenness of thecolored fabric; and b is a measure of the yellowness or blueness of thecolored fabric. Greater ΔE_(p) value result in a higher intensity of thecolor.

The acuity ratio (AR) was calculated by printing the black and red 4 pt.line in both warp and fill directions and measuring the greatest widththat the ink wicked away from the line under a light microscope anddividing by the theoretical line width.

The results in Table 1 demonstrate the effects of changing concentrationof repellant finish, type of repellant finish or cationic chemical, andtotal solids add-on.

1-64. (canceled)
 65. A method comprising the steps of: applying acoating to at least a first side of a textile, said coating havingcationic and repellant properties; applying an image to the first sideof the textile with the coating thereon.
 66. The method according toclaim 65, wherein said step of applying a coating includes applying thecoating to the textile in an aqueous form.
 67. The method according toclaim 66, wherein said step of applying the coating further includesdipping the textile into the aqueous form of the coating.
 68. The methodaccording to claim 66, further including the step of squeezing thetextile between rollers after the step of applying the coating and priorto the step of applying the image.
 69. The method according to claim 66,further including the step of drying the textile after the step ofapplying the coating and prior to the step of applying the image. 70.The method according to claim 65, wherein said step of applying theimage includes applying the image with digital printing.
 71. The methodaccording to claim 65, wherein said step of applying the image includesapplying the image with an ink jet printer.
 72. (canceled)
 73. A devicecomprising a textile with an image thereon, the image having a colorintensity of greater than 60.7 for the color red.
 74. A devicecomprising a textile with an image thereon, the image having a colorintensity of greater than 56.7 for the color yellow.
 75. A devicecomprising a textile with an image thereon, the image having a colorintensity of greater than 56.3 for the color blue.
 76. A devicecomprising a woven textile with an image thereon, the image having anacuity ratio of about 1 in the warp direction of said textile.
 77. Adevice comprising a woven textile with an image thereon, the imagehaving an acuity ratio of between about 1 and about 1.3 in the filldirection of said textile.